where \(f^{\text{1D},i}\)  is 1-by-1 1D convolution for the \(i\) -th axis heatmaps, \(\text{avg}^i\)  is i-axis marginalization by averaging, \(f^\text{ up}\)  denotes up-sampling by deconvolution, and \(\psi \)  is a 1D convolution layer followed by reshaping operation.
Finally, the continuous 3D coordinates of joints \(J \in \mathbb {R}^{N_J \times 3}\)  and vertices \(V \in \mathbb {R}^{N_V \times 3}\)  can be obtained by applying soft-argmax on the discrete heatmaps \(H_J\)  and \(H_V\) , respectively.
More details can be found in [1]} and supplementary material.
